| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a switching device to determine the switching status of a push button switch having two sets of switches arranged in parallel, which can determine the switching status even when any of wirings connecting switches is broken. <P>SOLUTION: Diodes 27a and 27b are provided in parallel for first and second switches SWa and SWb, respectively, and contact terminals 24a and 24b on one side are connected to input terminals Fa and Fb of a vehicle control part 10 via wirings A and B, respectively, and contact terminals 25a and 25b on the other side are connected to an input terminal Fc via a common wiring C. When the input terminals that are normally pull-up are changed one by one to an electric potential L by an abnormality detection signal generation circuit 13, the electrical potentials of the other input terminals change depending on the ON and OFF status of the respective switches, existence of disconnection, and the permission of electric flow by the diodes. Thus, the switching status of the first and the second switches can be determined from the pattern of change in the electric potentials of the input terminals Fa, Fb, Fc even when there is a disconnection. <P>COPYRIGHT: (C)2012,JPO&INPIT |
